Attention deficit hyperactivity disorder (ADHD) constitutes one of the most common childhood syndromes and its negative outcomes on all the child's functional domains have been consistently reported in the literature. As a result, their early identification is becoming a topic of increasing concern among the researchers from the field. However, given that many of the behaviors of interest are normative behaviors during this period, diagnosis in preschool years is controversial. Specifically, from a developmental perspective, although it is well known that high levels of motor activity, poor self control, and lack of attention are typical during these years, both expression and intensity of these behaviors are markedly higher on the group of ADHD preschool children. Consequently, their negative interference with daily living, produce significant maladjustments in the child's natural settings. All these ideas justify the need of considering and studying the most appropriate assessment techniques to reliably identify the deficits of ADHD in preschool children. On the basis of these statements, this paper offers a theoretical overview of the most recent developments regarding ADHD assessment and intervention techniques directed to the prevention of cognitive deficits as well as the achievement of a better school and social adjustment of ADHD preschool children.